Parallel feeding mechanism for sewing machines



Oct. 14, 1969 R. A. HAYES PARALLEL FEEDING MECHANISM FOR SEWING MACHINES Filed Feb. 21, 1968 t d) v mvsmon ROBERT A. HAYES flfmui MM;

'7 Sheets-Sheet 1 ATTORNEYS R. A. HAYES Oct. 14, 1969 PARALLEL FEEDING MECHANISM FOR SEWING MACHINES Filed Feb. 21, 1968 7 Sheets-Sheet 2 8 mar.

INVENTOR ROBERT HAYES BY n I Z Z f LATTORNEY5 Oct. 14, 1969 R. A. HAYES PARALLEL FEEDING MECHANISM FOR SEWING MACHINES Filed Feb. 21, 1968 7 Sheets-Sheet 5 INVENTOR ROBERT A. HAYES [:QI'AIIIH n I d l n p -1 J Q, 411 Q 4 Oct; 14, 1969 R. A. HAYES 3,472,188

PARALLEL FEEDING MECHANISM FOR SEWING MACHINES Filed Feb. 21, 1968 7 Sheets-Sheet 4 ROBERT A. HAYES BY Wa t 1mm W 5 @Wv ATTORNEYS Oct. 14, 1969 R. A. HAYES 3,472,183

PARALLEL FEEDING MECHANISM FOR SEWING MACHINES Filed Feb. 21, 1968 7 Sheets-Sheet 5 IFIGJZ ass" v INVENTOR ROBERT A HAYEB 4&2 Via /0122M,

ATTORNEYS 0a. 14, 1969 R. A. HAYES 3,472,188

PARALLEL FEEDING MECHANISM FOR SEWING MACHINES Filed Feb. 21, 1968 v Sheets-Sheet 6 INVENTOR 7 ROBERT A. HAYES Oct. 14, 1969 HAYES 3,472,188

PARALLEL FEEDING MECHANISM FOR SEWING MACHINES Filed Feb. 21, 1968 '7 Sheets-Sheet '7 2B 2n Rbganmmves 7 21204, WMJZLL ORNEYS United States Patent 3,472,188 PARALLEL FEEDING MECHANISM FOR SEWING MACHINES Robert A. Hayes, Franklin Park, Ill., assignor to Union Special Machine Company, Chicago, Ill., a corporation of Illinois Filed Feb. 21, 1968, Ser. No. 707,036 Int. Cl. Db 27/24 US. Cl. 112-215 28 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a feeding mechanism for sewing machines providing a perfectly level feed motion to a feed dog as it travels above the throat plate. The feed dog is carried by a feed bar, and the feed bar has opposite end portions, each carrying a slidable member. The slidable members translate the motion of a pair of eccentrics into linear movement for simultaneously lifting and lowering the end portions of the feed bar. Eccentric means are further provided for producing the feeding and retracting motion to the feed bar and thereby the feed dog.

Many sewing machines include what is commonly termed a four-motion feeding mechanism for moving a feed dog in a closed generally oval-shaped path. In one such conventional mechanism the feed bar is pivotally secured at its rearward end to a shaft of a rocker arm. The vertical motion imparted to the forward end of the feed bar is therefore greater than the motion imparted to the rear portion, and as a result upon the back stroke, if the feed dog is long, the rear portion of the feed dog will back feed toward the end of the feeding cycle. Furthermore, in the absence of parallelism of the feed dog relative to and above the throat plate during the feeding stroke the fabric being sewn may also be undesirably gathered and/or stretched during the sewing operation.

In keeping with the foregoing, it is a primary object if this invention to provide a novel feeding mechanism of the four-motion type which eliminates the latter-noted distadvantages by providing perfectly straight line motion to a feed dog during the feeding stroke (as well as the retracting stroke), and additionally includes adjusting means for tilting the feed dog when it is desired to gather or stretch the fabric being sewn.

A further object of this invention is to provide a novel feeding mechanism in which a member is mounted for free sliding movement relative to and at opposite ends of a feed bar, means are provided for generating eccentric motion, and the eccentric motion generating means and the sliding members are so coupled together as to impart feeding and retracting movements to feed dog carried by the feed bar and lifting and lowering movements to the feed bar substantially at the termination of the retracting and feeding movements, respectively, thereby imparting four-motion feed to the feed bar and the feed dog carried thereby.

Another object of this invention is the provision of a novel feeding mechanism of the type described wherein the eccentric motion generating means is an eccentric associated with each of the sliding members for imparting the lifting and lowering movements to the feed bar, and a further eccentric is coupled by a pitman to the feed bar for imparting the feeding and retracting movements thereto.

Still another object of this invention is the provision of a novel feeding mechanism constructed in the manner heretofore set forth wherein one of the lifting and lowering eccentrics is connected to the associated sliding member by a crank arm, and the other of the lifting and lowering eccentrics is mounted for rotation relative to and within the other sliding member.

A further object of this invention is to provide a novel feeding mechanism as set forth heretofore wherein the lifting and lowering eccentrics are each carried by a rotatable shaft, and means are provided for imparting rotation from one of the shafts to the remaining shaft.

A further object of this invention is to provide a feed mechanism of the type set forth wherein adjusting means are provided for tilting the feed dog relative to a throat plate by selectively adjusting one of the lifting and lowering eccentrics relative to its sliding member in selected positions rotationally out of phase with the remaining lifting and lowering eccentric and its associated sliding member.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claimed subject matter, and the several views illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a fragmentary sectional view taken generally longitudinally through a sewing machine, and illustrates the feeding mechanism positioned beneath the throat plate, and a main drive shaft for operating the feeding mechanism.

FIGURE 2 is a sectional view of an. upper portion of the sewing machine, and illustrates the manner in which a reciprocal needle bar is driven from the main shaft.

FIGURE 3 is a side elevational view looking from the left in FIGURE 1, and illustrates a feed dog carried by a feed bar of the feeding mechanism, and means at opposite end portions of the feed bar for imparting lifting, lowering, feeding and retracting movements thereto.

FIGURE 4 is a top view of the machine of FIGURE 1 with certain parts removed for clarity, and illustrates the drive connection between one end of the feed bar and the main shaft.

FIGURE 5 is an enlarged perspective view of the feeding mechanism, and illustrates a pitman coupled between an eccentric carried by the main shaft and the feed bar for imparting reciprocal feeding and retracting movement thereto.

FIGURE 6 is a fragmentary view of a pitman eccentrically driven from the main shaft for lifting and lowering one end of the feed bar in synchronous unison with the lifting and lowering movement of an opposite end of the feed bar by an eccentric connected to the main shaft.

FIGURE 7 is a sectional view taken generally along line 7-7 of FIGURE 4, and illustrates the manner in which a looper rock shaft is driven by an eccentric and a pitman from the main drive shaft.

FIGURE 8 is a side view partially in section of the feed bar of FIGURE 5 with portions thereof removed for clarity, and illustrates a pair of sliding members coupling end portions of the feed bar to a pair of eccentrics.

FIGURE 9 is an end view looking right to left in FIG- URE 8, and more clearly illustrates the sliding connection between the feed bar and the main shaft eccentric.

FIGURE 10 is a top view of the feed bar, and illustrates a pivot pin for connecting the feed bar by the pitman and its associated eccentric to the main shaft.

FIGURE 11 is an exploded view of a right hand portion of the feed bar of FIGURE 5, and schematically illustrates the manner in which the main drive shaft is coupled to the feed bar for imparting feed and retractin g movements thereto.

FIGURE 12 is a fragmentary top plan view of another feeding mechanism constructed in accordance with this invention, and illustrates a pair of shafts which are rotated in unison, and eccentrics coupling terminal ends of the shafts to opposite ends of the feed bar for imparting lifting and lowering movements thereto.

FIGURE 13 is a fragmentary side view of the mechanism shown in FIGURE 12 as viewed from the left, and more clearly illustrates the manner in which eccentric portions of the shafts are rotatably journalled in sliding members at opposite ends of the feed bar but includes additionally the means for imparting feeding and retracting movements thereto.

FIGURE 14 is a fragmentary side view of another feeding mechanism of this invention, and illustrates a pitman connected between the feed bar and a secondary driven shaft for imparting reciprocal motion to the feed bar and a feed dog carried thereby.

FIGURE 15 is a fragmentary sectional view taken generally along line 1515 of FIGURE 14, and more clearlyillustrates the manner in which the shaft is eccentrically connected to the pitman and a member mounted for sliding movement relative to an end portion of the feed bar.

FIGURE 16 is an exploded view of another feeding mechanism of this invention, and illustrates a plurality of sliding members for translating the eccentric motion of a pair of shafts into the four-motion movement of a feed bar formed from three assembled plates.

FIGURE 17 is a fragmentary top perspective view partly in section of the feeding mechanism of FIGURE 16, and illustrates a pulley belt for synchronously rotating a secondary driven shaft from a main drive shaft.

FIGURE 18 is a side view of the feeding mechanism looking from the left in FIGURE 17, and more clearly illustrates the manner in which the sliding members are assembled relative to the feed bar.

FIGURE 19 is a sectional view taken generally along line 1919 of FIGURE 18, and more clearly illustrates the coupling between the main drive shaft and the sliding members at one end of the feed bar.

FIGURE 20 is a fragmentary sectional view taken generally along line 2020 of FIGURE 18, and more clearly illustrates the manner in which the driven shaft is coupled to the opposite end portion of the feed bar.

A sewing machine incorporating a feeding mechanism constructed in accordance with this invention comprises a bed casting 16 which includes a column 17, and an overhanging arm 18 terminating in a needle head 20. The column 17 is conventionally secured to the bed casting 16 by means of screws 21 (FIGURE 4) or simi lar conventional fastening means.

A main two-part drive shaft 22 (FIGURES 1 and 4) is journalled for rotation within the casting 16 by bushings 23, 24 and 25. A drive pulley 26 is fixedly secured to an end portion 27 of the shaft 22. The shaft 22 includes a crank 28 articulately coupled to a pitman 30 which is in turn articulately connected to a needle lever 31 pivotally mounted upon a needle lever stud 32. The needle lever 31 is in turn connected to a needle bar 33 reciprocally mounted in the needle head 20. The rotary motion of the main shaft 22 is thereby transmitted to the needle bar 33 which in turn reciprocates a needle 34- carried thereby in a conventional manner.

A looper 35 (FIGURES 3 and 4) is moved in the generally elliptical path indicated by the dash line in FIGURE 4 by a lever crank assembly 36 (FIGURES 1 and 4) and an eccentric assembly 37 (FIGURES l and 7). The looper driving lever crank assembly 36 includes a pitman 38 (FIGURE 1) having an upper end portion conventionally secured to a ball stud 40 and a lower end portion similarly conventionally secured to a ball stud 41. The ball stud 40 is secured to a pair of collars 42, 43 which are in turn fastened by screws 44 to axially opposed parts 45, 46 of the two-part shaft 22. The ball stud 41 is in turn rigidly attached to a looper drive lever rock shaft 47 to which in turn is fixedly se- 4 cured a looper drive lever 48 (FIGURE 4). The drive lever 48 thereby oscillates back and forth and imparts similar motion to the looper 35 through a ball point 50, an adjustable pitman 51, and a ball joint 53 (FIGURE 3) which includes a ball stud carried by a looper 56 (FIGURE 3).

The looper avoid motion is generated by the eccentric assembly 37 which includes a pitman 53 (FIGURE 7) eccentrically connected at one end to the shaft 22 and pivotally connected at an opposite end to a lever 54. The rotation of the shaft 22 thereby lifts and lowers the lever 54 which through a rigid connection rocks a looper rock shaft 55 (FIGURES 4 and 7). A looper holder 56 carrying the looper 35 is rigidly secured to the looper rock shaft 55. The combined motions of the mechanisms 36, 37 thereby impart the generally elliptical motion to the looper 35 in synchronism with the reciprocal motion of the needle 34.

The machine 10 further includes chain cutting knife mechanism 58 (FIGURES 1, 3 and 4) which includes a stationary blade 60 and a reciprocating blade 61 carried by an upper end portion of a lever 62 fixed by a screw 63 to a shaft 64 journalled in a conventional manner in the bed casting 16. The lever 62 is connected by conventional coupling means 65 (FIGURE 1) to a crank arm 66 having an upper end portion (unnumbered) embracing an eccentric 67 fixed to the shaft 22. The connection between the shaft 22 and the lever 62 is such as to reciprocate the lever 62 and the blade 61 carried thereby during each complete revolution of the main shaft 22, thereby effecting a cutting action between the blades 60, 61 during each revolution of the main shaft 22.

Reference is now made particularly to FIGURES 3, 5 and 8 through 11 of the drawings which illustrate the novel feeding mechanism 15 to which the invention is primarily directed. The feeding mechanism 15 includes a feed bar 70 formed by an upper plate '71, a lower plate 72 and a block 73 (FIGURE 8). A plurality of identical fastening means 74 through 76 rigidly secure the plates 71, 72 and the block 73 in assembled relationship, as is best illustrated in FIGURE 8 of the drawings. The fastening means 75, 76 further secure a bracket 77 atop the plate 71. The bracket 77 includes a channel 78 into which is slidably received an apertured feed dog shank 80 of a feed dog 81. A screw 82 passes through an elongated slot (unnumbered) of the shank 80 and is in turn threadably fastened in a threaded bore 83 of the bracket 77. Vertical adjustment of the feed dog 81 can be thereby effected simply by loosening the screw 82, adjusting the feed dog 81 as desired, and thereafter retightening the screw 82.

The feed bar 70 of the feeding mechanism 15 is supported at opposite end portions (unnumbered) by a pair of sliding members or blocks 84, 85 which in addition to supporting the feeding bar 70 also function to translate eccentric motions into generally linear movements for lifting and lowering the feed bar 70. The sliding member 84 rotatably journals an eccentric 87 of the main drive shaft 22. The sliding member 85 is similarly provided with a circular bore 88 in which is received a shaft 90. A pair of collars 91, 92 are secured to the shaft at opposite sides of the feed bar 70 by screws 89. An end portion (unnumbered) of the shaft 90 projecting to the right of the collar 92, as viewed in FIGURE 4 is fixedly connected to a lift crank 93 which is in turn fixedly secured to a shaft 94 (FIGURE 4). The shaft 94 is journalled for rocking movement in a bushing 95 in a journalling bracket 96 secured to the bed casting 16 by screws 97 (FIGURES 4 and 6). A lever 98 having a bifurcated end is fixedly secured to the shaft 94 by a screw 100, While an opposite end portion of the lever 98 is connected to a pitman 101 coupled to an eccentric 102 carried by the main shaft 22.

As the main shaft 22 rotates the eccentric end portion 87 thereof generates eccentric motion which is translated by the sliding member 84 into lifting and lowering movement of the right hand end of the feed bar 70 as viewed in FIGURES 5 and 8 due to the free sliding motion of the member 84 in a generally horizontal plane. The same rotation of the drive shaft 22 rotates the eccentric 102 (FIGURE 6) which through the pitman 101 and the lever 98 imparts rocking movement to the shaft 94. The rocking of the shaft 94 thereby imparts lifting and lowering movement to the sliding member 85 through the shaft 90 and the lift crank 93, it being again noted that the member 85 is free to slide in a horizontal plane. The lifting and lowering movements imparted to the feed bar 70 are, of course, normally applied to the end portions of the feed bar 70 through the members 84, 85 in a synchronous, simultaneous manner such that the feed bar 70 is lifted and lowered as a whole in a generally vertical plane.

The feed bar 70 is reciprocated to impart feeding and retracting movements thereto and to the feed dog 81 carried thereby by means of an eccentric 105 (FIGURES 5 and 11). The eccentric 105 is fixed to an eccentric end portion 106 of the main drive shaft 22 by akey 107. The eccentric 105 is in turn received in a circular bore 108 of a pitman 110. The pitman 110 is in turn connected to the feed bar 70 by a pin 111 force-fit into an aperture 112 of the block 73 (FIGURE 8). An aperture .113 in the pitman 110 journals the pitman for pivotal movement about the pin 111, while a washer 114 and a nut 115 threadably secured to a threaded end portion 116 of the shaft 22 maintains the latter-noted components in assembled relationship between the feed bar 70 and the shaft 22.

During the rotation of the shaft 22 eccentric motion generated by the combined eccentrics 105, 106 imparts horizontal reciprocal movement to the feed bar 70 through the pitman 110 and the pin 111, it being noted that during the reciprocal movement of the feed bar 70 the feed bar 70 is free to slide relative to the members 84, 85. It should be particularly noted that during the feeding movement of the feed dog 81 (right-to-left in FIGURE 3) the relative sliding movement between the feed bar 70 and the members 84, 85 permits the feed dog 81 to move in a generally perfect straight line with the teeth (unnumbered) thereof positioned above an upper surface 118 of a conventionally apertured throat plate 119. At the end of the feed stroke the simultaneously lowering of the feed bar end portions (unnumbered) causes the general linear lowering of the feed dog 81, and upon the retracting stroke the feed bar 70 and the feed dog 81 are again moved generally perfectly linearly in a horizontal plane. Thus, the path of travel of the feed bar 70 and the feed dog 81 carried thereby is generally of a closed rectangular configuration, it being particularly noted that straight line motion is imparted to the feed dog 81 during both the feeding and retracting strokes i.e. when the teeth of the feed dog 81 are respectively above and below the upper surface 118 of the throat plate 119. It is, of course, due to the perfectly linear movement of the feed dog 81 during the feed stroke and the simultaneous lowering of the opposite end portions of the feed bar 70 during the lowering stroke that the mechanism prevents undesired backfeeding of the fabric being sewn.

It is also at times desirable to alter the inclination of the feed dog 81 relative to the upper surface 118 of the throat plate 119 and/or alter the stitch length which is determined by the feed stroke of the pitman 110 and its associated eccentric 105 and eccentric shaft portion 87. For example, by tilting the feed dog 81 high in front the fabric being sewn will be gathered whereas tilting the feed dog high in the rear would result in the fabric being stretched during a sewing operation. In accordance with this invention, the feed bar 70 is tilted when it is desired to tilt the feed dog 81 carried thereby for either stretching or gathering the fabric being sewn. The tilting of the feed bar 70 is accomplished by loosening the screw 100 (FIGURE 6), advancing or retarding the lift crank 93 by rotating the shaft 94, and thereafter retightening the screw 100. As can be best visualized in FIGURE 3, this adjustment automatically lifts or lowers the leftmost end portion of the feed bar 70 resulting in the automatic respective tilting of the forward end portion of the feed dog 81.

In order to alter the stitch length it is merely necessary to remove the eccentric and substitute another eccentric to alter the stitch length as desired. This can be done rapidly in accordance with the present invention by removing the nut and the collar 114, and replacing the eccentric 105 with another of the proper eccentricity. It should be particularly noted that changing the eccentric 105 in no way affects the lifting and lowering of the feed bar 70 and the feed dog 81 carried thereby, while retarding or advancing the lifting lever 93 likewise in no way affects the feeding and retracting motion heretofore described except for the tilted position of the feed dog 81 relative to the surface 118 of the throat plate 119.

Another feeding mechanism constructed in accordance with this invention is illustrated in FIGURES 12 and 13 of the drawings, and is generally designated by the reference numeral 120. The feeding mechanism 120 is similar to the feeding mechanism 15 and includes a feed bar 121 defined by a pair of plates 122, 123 having end portions (unnumbered) maintained in spaced relationship by a block 124 and a plurality of fasteners 125 through 127, the latter two of which secure a bracket 128 carrying a feed dog 130 to the feed bar 121. The left end of the shaft 22 as viewed in FIGURE 12 is identical to that illustrated in FIGURE 11. Therefore, the lifting and lowering motion of the right hand end portion of the feed bar 121 as viewed in FIGURE 13 is identical to that heretofore described relative to the feeding mechanism 15. Furthermore, the motion of the eccentric 105 imparts the feeding and retracting movement to the feed bar 121 in a manner also identical to that heretofore described in conjunction with the feeding mechanism 15.

The primary difference between the feeding mechanisms 15 and 120 is the manner in which the left end portion (unnumbered) of the feed bar 121 as viewed in FIGURE 13 is lifted and lowered in synchronism with the right hand end portion thereof.

In lieu of the lift crank 93 (FIGURE 4) which is rocked by the eccentric 102 connected to the driving shaft 22, a sliding member 131 (FIGURE 13) between the plates 122, 123 is lifted and lowered by an eccentric end portion 132 of a shaft 133. The eccentric end portion 132 is received in a bore 134 of the Sliding member 131, and a pair of locating collars 135, 136 are fastened by screws 139 to the eccentric end portion 132 at opposite sides of the plates 122, 123, as viewed in FIGURE 12. The eccentricities of the eccentric end portions 132, 87 are identical, and upon simultaneous synchronous rotation thereof the end portions (unnumbered) of the feed bar 121 are lifted and lowered simultaneously to impart linear lifting and lowering movement to the feed bar 121 and the feed dog 130 carried thereby.

The eccentric end portions 87, 132 are driven simultaneously and synchronously by means of a toothed timing belt 137 entrained about two pulleys 138, 140 secured to the respective shafts 133, 22 by one or more screws 141, 142. Since the pulleys 138, 140 are of the same diameter the rotation of the shaft 22 drives the pulleys 138, 140 at a 1 to 1 relationship whereupon the eccentric end portions 132, 87 generate eccentric movement which is translated by the sliding members into equal and simultaneous lifting and lowering of the feed bar end portions, the feed bar 121 itself, and the feed dog 130 carried thereby.

The feeding mechanism 120 also includes means for tilting the feed dog 130 relative to the throat plate to obtain the high in front or high in rear tilted movement heretofore mentioned relative to the feed dog 81. In the instant embodiment of the invention the feed bar 121 is tilted by loosening the screw 141, rotating the shaft 133 clockwise or counterclockwise, and thereafter retightening the screw 141. The left end portion of the feed bar 121 as viewed in FIGURE 13 can thereby be selectively raised or lowered to respectively raise or lower the forward end portion of the feed dog 130.

Another feeding mechanism constructed in further accordance with this invention is fully illustrated in FIG- URES 14 and 15 of the drawings, and is generally designated by the reference numeral 150. The feeding mechanism 150 includes a feed bar 151 formed by a pair of plates 152, 153 and a block 154, the latter three elements being connected to each other by a plurality of fasteners 155 through 157. The fasteners 156, 157 also secure a bracket 158 carrying a feed dog 160 to the upper plate 152.

The feeding mechanism 150 is similar to the feeding mechanism 120 in that opposite end portions (unnumbered) of the feed bar 151 are simultaneously lifted and lowered by eccentric end portions 161, 162 of respective shafts 163, 164, the said end portions 161, 162 having the same amount of eccentricity. The shafts 163, 164 correspond to the respective shafts 133, 22 of the feeding mechanism 120, and are driven by pulleys and a timing belt (not shown) corresponding to the pulleys 138, 140 and the timing belt 137 of FIGURE 12. The eccentric end portions 161, 162 are also received in circular bores (unnumbered) of respective sliding members 165, 166. Therefore, upon the simultaneous and synchronous rotation of the shafts 163, 164 the eccentric end portions 161, 162 synchronously and simultaneously lift and lower the feed bar 151 in a manner identical to that heretofore described in conjunction with the feeding mechanism 120.

The basic difference between the feeding mechanisms 120, 150 is the manner in which the feed bar 151 is re ciprocated during the feeding and retracting movements thereof. As opposed to the driving connection between the main driving shaft 22 (FIGURES 12 and 13) and the feed bar 121 by the pitman 110 of the mechanism 120, the reciprocating feeding and retracting movements are imparted to the feed bar 151 by the rotation of the secondary shaft 163. As is best illustrated in FIGURE 15, the shaft 163 includes an eccentric terminal end 167 to which is secured an eccentric 168 by a key 170. A collar 171 and a nut 172 which are removed in FIGURE 14 secure a pitman 173 upon the eccentric 168. An opposite end of the pitman 173 is pivotally secured to a pin 174 which is force-fit in a bore (not shown) of the block 154. Upon the rotation of the shaft 163 the combined motion of the eccentric terminal end portion 167 and the eccentric 168 imparts the feeding and retracting movement to the feed bar 151 and the feed dog 160 carried thereby in a manner heretofore described, it being again noted that the shaft 163 is driven by a timing belt from the main shaft 164 as in the case of the feeding mechanism 120.

The feed bar 151 of the feeding mechanism 150 may also be tilted to include the feed dog 160 in the manner described relative to the feeding mechanism 120. Furthermore, by substituting other eccentrics for the eccentric 168 the stitch length of the mechanism 150 can be changed as desired in the manner heretofore described.

Another feeding mechanism 180 is fully illustrated in FIGURES 16 through 20 of the drawings, and includes a feed bar 181 formed from three plates 182 through 184 which are secured to each other by a pair of screws 185, 186 which are received in oversized apertures 187 of the plates 182, 183 and threadably received in threaded bores 188 of the plate 184. A pair of feed dogs 190, 191 include respective legs or shanks 192, 193 which are positioned in slots 194, 195 of the plate 183. Respective screws 196, 197 pass through elongated slots (unnumbered) of the shanks 192, 193 and through oversized openings 198 of the plate 183. The screws 196, 197 are threadably received in threaded apertures 200, 201 of the plate 184. The oversize of the apertures 198 prevents the screws 196, 197

from binding as they are tightened which would otherwise occur if the apertures 198 were threaded. It is to be also noted that the elongated slots (unnumbered) permit the feed dogs 190, 191 to be adjusted vertically in the manner heretofore fully described relative to the feeding mechanism 15.

The left end portions (unnumbered) of the plates 182, 184 are provided with identical leftwardly opening rectilinear recesses 202, 203 while the left hand portion of the plate 183 is relieved at 204. The rightmost end portions of the plates 182, 184 as viewed in FIGURE 16 are similarly provided with rightwardly opening recesses 205, 206 while the plate 183 is provided with a downwardly opening recess 207.

A block or member 208 is slidably received in the recesses 202, 203, and is in turn provided with a bore 210 in which is received a bushing 211. The bushing 211 is fixed to an eccentric end portion 212 of a shaft 213 by a key 214. A locking collar 215 and a nut 216 threadably received upon an end portion 217 of the shaft 213 maintain the bushing 211 and the block 205 secured upon the end portion 212 of the shaft 213.

The recesses 205 through 207 are similarly provided with sliding blocks or members 220 through 222. A pair of bushings 223, 224 and an eccentric 225 are housed within apertures or bores (unnumbered) of the blocks 220, 222 and 221, and the latter-noted bushings and eccentric are fixedly secured to an eccentric end portion 226 of a main drive shaft 227 by a key 228. A collar 230 and a nut 231 maintain the members 220 through 222, the bushings 223, 224 and the eccentric 225 in assembled relationship upon the eccentric end portion 226 of the shaft 227.

The shaft 227 is a main drive shaft corresponding to the shaft 22, and rotation of the shaft 227 is imparted to the shaft 213 by a timing belt 232 and a pair of pulleys 233, 234 of equal diameters. Screws or similar fastening means 235, 236 fixedly secure the pulleys 233, 234 to the respective shafts 213, 227. However, the screws 235 can be loosened and the shaft 213 rotated in the manner heretofore described relative to the feeding mechanism to alter the position of the feed bar 181 for tilting the feed dogs 190, 191 carried thereby.

Since the eccentric end portions 212, 226 of the respective shafts 213, 227 are of the same eccentricity, the simultaneous synchronous eccentric motion generated thereby is transmitted to opposite end portions (unnumbered) of the feed bar 181 through the blocks 208, 220, 221 and 222. The lifting and lowering movement is therefore imparted to the feed bar 181 by the block 208 at one end and the blocks 220, 222 at the opposite end, it being noted that during both lifting and lowering movements of the feed bar 181 the blocks 221 is free to slide vertically relative to the plate 183 due to the recess 207.

The rotation of the shaft 227 also rotates the eccentric 225 and the eccentric motion generated thereby is translated by the sliding member 221 into reciprocal movement of the feed bar 181 to impart thereto the feeding and retracting movement. During the reciprocation of the feed bar 181 the members 208, 220 and 222 are similarly free to slide in a horizontal plane relative to the feed bar. In this manner the initial rotary motion of the shafts 213, 227 is employed to impart four-motion movement to the feed bar 181, it being again particularly noted that the feeding and retracting movements thereof are substantially perfectly linear.

The stitch length of the feeding mechanism can, of course, be changed by removing the feed bar from the shafts 213, 227 in an obvious manner and substituting a different eccentric for the eccentric 225.

'While preferred forms and arrangement of parts have been shown in illustrating the invention, it is to be clearly understood that various changes in details and arrangement of parts may be made without departing from the spirit and scope of the invention as defined in the appended claimed subject matter.

I claim:

1. A feeding mechanism for sewing machines comprising a feed bar having opposite end portions, a feed dog carried by said feed bar, means for reciprocating said feed bar to impart feeding and retracting movements thereto, means for lifting and lowering said feed bar substantially at the termination of said retracting and feeding movements respectively, said lifting and lowering means including means coupled to said feed bar for generating eccentric motion, means for translating the eccentric motion of said eccentric motion generating means into generally linear movements for lifting and lowering said feed bar, and said translating means are a pair of members each mounted for free sliding movement relative to said feed bar at respective ones of said opposite end portions in directions generally parallel to said feeding and retracting movements.

2. The feeding mechanism as defined in claim 1 wherein said eccentric motion generating means is an eccentric rotatably coupled to each of said sliding members, and means for rotating said eccentrics.

3. The feeding mechanism as defined in claim 1 Wherein said eccentric motion generating means is an eccentric coupled in each of said sliding members, and means for selectively adjusting said eccentrics relative to each other to tilt said feed bar and the feed dog carried thereby.

4. The feeding mechanism as defined in-claim 1 wherein said eccentric motion generating means isan eccentric coupled to each of said sliding members, "means for moving said eccentrics, said eccentric moving means being a pair of shafts each of which carries one of said eccentrics, means for rotating one of said shafts, and means coupling said one shaft to said remaining shaft for imparting movement to the latter shaft and the eccentric carried thereby.

5. The feeding mechanism as defined in claim 1 wherein said eccentric motion generating means is an eccentric coupled to each of said sliding members, means for moving said eccentrics, said eccentric moving means being a pair of shafts each of which carries one of said eccentrics, means for rotating one of said shafts, means coupling said one shaft to said remaining shaft for imparting movement to the latter shaft and the eccentric carried thereby, and means for driving said reciprocating means by one of said pair of shafts.

6. The feeding mechanism as defined in claim 1 wherein said eccentric motion generating means is an eccentric coupled to each of said sliding members, means for moving said eccentrics, said eccentric moving means being a pair of shafts each of which carries one of said eccentrics, means for rotating one of said shafts, and means entrained about said shafts for imparting movement to the remaining shaft upon the rotation of said one shaft.

7. The feeding mechanism as defined in claim 1 wherein said eccentric motion generating means is an eccentric coupled to each of said sliding members, means for moving said eccentrics, said eccentric moving means being a pair of shafts each of which carries one of said eccentrics, means for rotating one of said shafts, means entrained about said shafts for imparting movement to the remaining shaft upon the rotation of said one shaft, and said last-mentioned means is a toothed drive belt.

8. The feeding mechanism as defined in claim 1 including a throat plate relative to which said feed bar normally moves in generally parallel relationship during the feeding movement thereof, and means for selectively tilting said feed bar relative to said throat plate to alter the inclination of said feed bar during its feeding movement.

9. The feeding mechanism as defined in claim 1 including a throat plate relative to which said feed bar normally moves in generally parallel relationship during the feeding movement thereof, means for selectively tilting said feed bar relative to said throat plate to alter the inclination of said feed bar during its feeding movement,

said reciprocating means including an eccentric carried by a rotary shaft, a pitman coupled between said eccentric and said feed bar for reciprocating the latter upon the rotation of said shaft and the eccentric carried thereby, and means for detachably securing said eccentric to said shaft to facilitate the replacement of the eccentric by another and different eccentric thereby altering the normal length of feed of said feed bar.

10. The feeding mechanism as defined in claim 1 wherein said eccentric motion generating means is an eccentric coupled to each of said sliding members, a first of said eccentrics being directly coupled within one of said members, a second of said eccentrics being exteriorly of and indirectly coupled to the other of said members, and means for moving said eccentrics to synchronously move said member for simultaneously lifting and lowering said opposite end portions, said feed bar and the feed dog carried thereby.

11. The feeding mechanism as defined in claim 10 wherein said moving means includes a rotary shaft carrying said first eccentric.

12. The feeding mechanism as defined in claim 10 wherein said moving means includes a shaft carrying said second eccentric, and crank-arm means for coupling said second eccentric to said other member.

13. The feeding mechanism as defined in claim 10 wherein said moving means includes a pair of shafts, each of said eccentrics being carried by an associated one of said shafts, means for rotating one of said shafts, and means coupling said one shaft to said remaining shaft for imparting movement to the latter shaft and the eccentric carried thereby.

14. The feeding mechanism as defined in claim 10 wherein said reciprocating means includes an eccentric carried by one of said shafts, and a pitman coupled between said last-mentioned eccentric and said feed bar for reciprocating the latter upon the movement of said one shaft.

15. The feeding mechanism as defined in claim 10 wherein said moving means includes rotary and rocking shafts to which said first and second eccentrics are respectively connected, crank-arm means for coupling said second eccentric to said other member, and means for rotating and rocking the respective rotary and rocking shafts to synchronously move said members.

16. The feeding mechanism as defined in claim 15 wherein said last-mentioned means includes means for rotating said rotary shaft, and means coupled between said shafts for converting the rotating motion of said rotary shaft into rocking motion of said rocking shaft.

17. The feeding mechanism as defined in claim 15 wherein said reciprocating means includes an eccentric carried by said rotary shaft, and a pitman coupled between said last-mentioned eccentric and said feed bar for reciprocating the latter upon the rotation of said rotary shaft.

18. The feeding mechanism as defined in claim 1 wherein said eccentric motion generating means is an eccentric rotatable relative to and within each of said members, a shaft carrying each of said eccentrics, means for rotating one of said shafts, and means between said shafts for rotating the remaining shaft by said one shaft.

19. The feeding mechanism as defined in claim 18 wherein said reciprocating means includes an eccentric carried by one of said shafts, and a pitman coupled between said last-mentioned eccentric and said feed bar for reciprocating the latter upon the rotation of said lastmentioned shaft.

20. The feeding mechanism as defined in claim 18 wherein said reciprocating means includes an eccentric carried by one of said shafts, a member receiving said last-mentioned eccentric and being mounted for sliding movement relative to said feed bar for translating eccentric motion into generally linear movement, and a pitman coupled between said last-mentioned eccentric and 11 said feed bar for reciprocating the latter upon the rotation of said last-mentioned shaft.

21. A feeding mechanism for sewing machines comprising a feed bar, a feed dog carried by said feed bar, means for reciprocating said feed bar to impart feeding and retracting movements thereto, means for lifting and lowering said feed bar substantially at the termination of said retracting and feeding movements respectively, said reciprocating means and said lifting and lowering means each including means coupled to said feed bar for generating eccentric motion, means mounted for sliding movement relative said feed bar in a direction generally normal to the feeding and retracting movements of said feed bar for translating the eccentric motion of one of said eccentric motion generating means into the feeding and retracting movements of said feed bar, and means mounted for sliding movement relative said feed bar in a direction generally parallel to the feeding and retracting movements of said feed bar for translating the eccentric motion of the other of said eccentric motion generating means into the lifting and lowering movements of said feed bar.

22. The feeding mechanism as defined in claim 21 wherein said feed bar is formed by a plurality of individual plates, each of said plates having recesses formed therein, and each of said sliding means includes a block mounted for sliding movement in recesses of said plates.

23. The feeding mechanism as defined in claim 21 wherein said feed bar is formed by a plurality of individual plates, each of said plates having recesses formed therein, each of said sliding means includes a block mounted for sliding movement in recesses of said plates, and at least two of said recesses are positioned with the longitudinal axes thereof offset 90 degrees relative to each other.

24. The feeding mechanism as defined in claim 21 wherein said feed bar is formed by a plurality of individual plates, each of said plates having recesses formed therein, each of said sliding means includes a block mounted for sliding movement in recesses of said plates, at least two of said recesses are positioned With the longitudinal axes thereof offset degress relative to each other, a first of said two recesses is formed in one of said plates, and the other of said two recesses is formed in another of said plates.

25. The feeding mechanism as defined in claim 21 wherein said feed bar is formed by a plurality of individual plates, and means for securing said first-mentioned and another feed dog in aligned relationship to one of said plates.

26. The feeding mechanism as defined in claim 21 wherein said sliding means are a plurality of sliding members mounted for sliding movement at opposite end portions of said feed bar, said eccentric motion generating means are defined by eccentrics housed within and rotatable relative to said members and means for imparting rotation to said eccentrics.

27. The feeding mechanism as defined in claim 26 wherein said rotation imparting means are a pair of syncronously rotated shafts.

28. The feeding mechanism as defined in claim 27 including means for drivingly rotating one of said shafts, and means coupling said shafts whereby rotation of said one shaft imparts rotation to said remaining shaft.

References Cited UNITED STATES PATENTS 2,012,606 8/1935 Hohmann 112-2l5 2,065,885 12/1936 Briggs et al. 112-215 2,894,471 7/1959 Pajor 1122l5 3,195,487 7/1965 Reeber 112-215 ALFRED R. GUEST, Primary Examiner 

